Now that the driver's buffer is stored on the adjd_s311_data private
object, the driver is a simple conversion to use only device-managed
functions in the probe.

The iio_triggered_buffer_setup() and iio_device_register() functions are
the only ones needing conversion.
And i2c_set_clientdata() is no longer required.
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210705071456.649659-2-aardelean@deviqon.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>